Cookies on the NHS website
We've put some small files called cookies on your device to make our site work.
We'd also like to use analytics cookies. These send information about how our site is used to services called Adobe Analytics, Hotjar and Google Analytics. We use this information to improve our site.
Let us know if this is OK. We'll use a cookie to save your choice. You can read more about our cookies before you choose.
I'm OK with analytics cookies Do not use analytics cookies
Search the NHS website
Search
My account
Health A-Z
Live Well
Mental health
Care and support
Pregnancy
Browse
More
Home Health A to Z
Red blood cell count
A red blood cell (RBC) count is a blood test that tells you how many red blood cells you have.
Red blood cells contain a substance called haemoglobin, which transports oxygen around the body.
The amount of oxygen that's delivered to your body's tissues depends on the number of red blood cells you have and how well they work.
A RBC count is usually carried out as part of a full blood cell (FBC) count.
Women usually have a lower RBC count than men, and the level of red blood cells tends to decrease with age.
A normal RBC count would be:
men – 4.7 to 6.1 million cells per microlitre (cells/mcL)
women – 4.2 to 5.4 million cells/mcL
The results of an RBC count can be used to help diagnose blood-related conditions, such as iron deficiency anaemia (where there are less red blood cells than normal).
A low RBC count could also indicate a vitamin B6, B12 or folate deficiency.
It may also signify internal bleeding, kidney disease or malnutrition (where a person's diet doesn't contain enough nutrients to meet their body's needs).
A high RBC count could be caused by a number of health conditions or health-related factors, including:
smoking
congenital heart disease
dehydration (for example, from severe diarrhoea)
low blood oxygen levels (hypoxia)
pulmonary fibrosis (a lung condition that causes scarring of the lungs)
Read more about the red blood cell count at Lab Tests Online UK.
Page last reviewed: 21 September 2018
Next review due: 21 September 2021
Support links
Home
Health A to Z
Live Well
Mental health
Care and support
Pregnancy
NHS services
Coronavirus (COVID-19)
NHS App
Find my NHS number
Your health records
About the NHS
Healthcare abroad
Contact us
Other NHS websites
Profile editor login
About us
Accessibility statement
Our policies
Cookies
© Crown copyright